Brakes - squidgy and pedal drops

[Asa-James]

Swapped the brakes on the nova tonight for 256mm items, went to bleed them up, one side was fine but the other needed some persuasion. Pumped on the pedal, and even tho the bleed nipple was open there was loads of resistance until it gave in and bled. Did this a couple more times with the same result only on one side. Took it for a quick spin and it stops in a straight line etc, but as I tried to lock the wheels up the pedal dropped to the floor, but with no loss of brakes (no heavy braking beforehand, so didn't
overheat)


Basically I'm thinking either the flexi has failed, so it hasn't bled properly leading to the squidgyness, or the master cylinder has gone dolally internally

servo works fine btw

Any views/opinions appreciated

[let_nova]

bleed again

start with furthest away from servo.

[bazil]

ive seen similar to what you described on my brothers astra mk4 estate, then about 4 days later the brakes failed completely on the motorway eek turns out when he was bleeding them he put to much pressure on the pedal and the seals had popped in the master cylinder. this motor had been sitting with no brake fluid in tho so the seals may have been dry and got damaged when being reused.

[dougie_boi]

ive seen similar to what you described on my brothers astra mk4 estate, then about 4 days later the brakes failed completely on the motorway eek turns out when he was bleeding them he put to much pressure on the pedal and the seals had popped in the master cylinder. this motor had been sitting with no brake fluid in tho so the seals may have been dry and got damaged when being reused.
i had the same problem with my cavalier and nova and after spending fortunes on master cylinders i found out it was because i was pushing the pedal all the way to the floor and it was turning the seals inside out in the master cylinder get another master cylinder mate and fit it but when your bleeding it up only push the pedal a 3rd or quarter of the way down mate they will eventually bleed up.

[Nova_Sean]

/off topic.
Just read your sig doug. Funny as ****!

[Stuart]

Does sound like the seals have inverted on the M/C

I always recommend using a gunsons easibleed. its £15-20 and WELL worth it! only use 10psi or so though lol

[bazil]

@ dougie, aye I've been over selous with the pedal before and that's the result, but at the time you realise what the problem is.

[dougie_boi]

@ dougie, aye I've been over selous with the pedal before and that's the result, but at the time you realise what the problem is. lol took me 4 master cylinders before i fanaly clicked as one channel or side bleeds up fine the you do the other and loose most of the pressure in the pedal lol

[MARTIN KELSON]

You have got the calipers on the right way round?

Bleed nipple at the top & not bottom as commonly done?

[craig green]

pad retaining spring correctly fitted?

[Asa-James]

yes and yes

(being a mechanic has its benefitslol:p)

talking to AW06 last night and the best way to describe the pedal drop wasits brakes normally, gets to the point where you expect it to lock up, and the pedal just drops. it keeps braking, at a reduced rate, but the pedal hits the bulkhead and loses its firmness. let it come back up and its fine again until you hit them hard. obviously i'm not using the car until its sorted lol

[craig green]

seriously mate, the symptoms sound exactly like what i had when the pad springs were on wrong on my 288's. get someone to watch the caliper when you depress the pedal. does it move (significantly?)

[let_nova]

abs lol